The present invention relates generally to thermostats used for heating and cooling systems, such as gas or electric forced air furnaces, gas or electric radiant heating furnaces, electric forced air air-conditioning systems, and electric heat pumps. Invention may also be suitable for other types of systems, including solar and solar electric heating and cooling systems.
Programmable thermostats typically use a screen, such as a liquid-crystal display (LCD), to display both operational functions and programming values. The user enters commands into the thermostat, such as for setting the current time and date and programming the thermostat, by pressing keys or pressing appropriate positions on a touch screen display. Programming conventional thermostats is often accomplished by selecting a series of different screens on the display. In addition, information relating to the status of the thermostat and the settings in the program controlling the thermostat is often accessible only by reviewing different screens on the display.
Although programmable thermostats hold out the promise of reducing the energy used by heating systems, the U.S. Environmental Protection Agency, which provides the ENERGY STAR certification for appliances and other devices, has expressed concern that potential energy savings are not being realized because of the difficulties consumers face trying to program conventional digital thermostats.